Radioactivity and Particles: Radioactivity

Radioactivity is a natural process where unstable atomic nuclei decay and release energy in the form of radiation.
There are three types of radiation: alpha (α), beta (β), and gamma (γ).
Alpha particles consist of 2 protons and 2 neutrons. These particles have a positive charge and are the largest and least penetrating form of radiation, but are highly ionising.
Beta particles are free, high-energy electrons and are smaller and quicker than alpha particles. They are more penetrating but less ionising than alpha particles.
Gamma radiation is an electromagnetic wave, not a particle, that carries a high amount of energy. It is the most penetrating form of radiation but the least ionising.
The neutron-rich nucleus releases beta particles during beta decay, while alpha decay occurs in heavy elements with too many protons and neutrons.
The count rate (activity) of a radioactive source decreases over time. The time taken for the activity to reduce by half is known as the ‘half-life’.
Radiation can ionise atoms, turning them into charged particles. These charged particles can cause damage to living cells.
Certain materials can stop or absorb different types of radiation. For example, paper or thin aluminium can stop alpha particles, while thicker aluminium or thin lead can stop beta particles. Thick lead or concrete is needed to stop gamma radiation.
Nuclear equations can be written to represent radioactive decay. In these equations, the total mass and charge (or atomic number) are conserved.
The dangers of radiation exposure include cancer and radiation sickness. Therefore, precautions are required when handling radioactive materials.
Geiger-Muller tubes are devices used to detect radiation. They measure the count rate or, in other words, how much radiation is present in a given area.
Unstable nuclei can become stable through radioactive decay. However, the stability of a nucleus cannot be influenced by changes in temperature, pressure or the presence of a magnetic or electric field.
Radioactive isotopes have applications in medicine (like cancer treatment and medical tracers), industrial processes, and in research like carbon dating.